Technical Field of the Invention
This invention relates generally to impact protection and more particularly to a protection system that reduces impact pressure resulting from an impact force.
Description of Related Art
Impact protection devices are known to reduce injury to a body part as a result of an impact. Most impact protecting devices include an outer shell and padding to protect the body part, which may be a limb, a joint, a portion of a limb, the back, ribs, the chest, the abdomen, the neck, and/or the head. For example, the impact protecting device is a helmet when the body part is a head.
For most helmets, the outer shell is a rigid material such as plastic, polycarbonate, etc. and the padding includes foam, air bladders, or a combination thereof. Vicis™ makes a football helmet that includes a softer outer shell, a 1½ inch thick core layer, and a foam based form liner.
As is generally accepted in the medical community, a concussion results from a sudden acceleration or deceleration of the head. Such rapid acceleration and declaration of the head can result from a car cash or violent shaking. This medical premise forms the basis for which helmets are tested. The testing of football helmets and other helmets involves dropping a headform wearing the helmet from various heights on to a platform and measuring g-forces from the impact. Thus, helmets are designed to pass g-force based testing.
G-force, however, is not a measure of force. It is a measure of acceleration or deceleration with respect to earth's gravitational field. Thus, for an impact, G-force is a measure of how fast the object decelerations with respect to the earth's gravity. In equation for, G-Force=a/g, where “g” is gravitational force of 32.2 ft/s2 and “a” is the deceleration of the object from impact, where a=v2/2*d, where “v” is the velocity at impact and “d” is the impact distance. With G-force being the unit of measure for testing helmets, the only variable in reducing G-Force is impact distance “d”. Thus, increasing impact distance is the only way to improve G-force based testing result of helmets. Accordingly, helmets are designed to increase impact distance.